The present invention relates to driving apparatus for rolling mill and more particularly, for vertical rolling mill having a vertical roll.
A conventional driving apparatus for a vertical rolling mill comprises a horizontal electric motor 1 and a gear mechanism 2 as shown in FIG. 2. the drive shaft 1a of the horizontal electric motor 1 extends to apply motive power to the gear mechanism 2 mainly made of bevel gears (not shown). The direction of transmission of the motive power is changed by an angle of approximately 90.degree. by a universal joint (not shown) disposed in the gear mechanism 2. The output shaft (not shown) of the gear mechanism 2 is connected to the upper end of an intermediate shaft 3 by an upper universal joint (not shown). The lower end of the intermediate shaft 3 is connected to the upper end of a vertical roll 5 by lower universal joint 4, thus transmitting the motive power to vertical roll 5.
The conventional driving apparatus of FIG. 2 has several disadvantages: gear mechanism 2 is large in size; the cost of gear mechanism 2 is high because of the need to use high-grade gears; maintenance of the gears in gear mechanism 2 is difficult; horizontal electric motor 1 needs a separate installation space; and separate equipment such as a concrete base is required for mounting motor 1.
In order to eliminate these disadvantages, another driving apparatus was developed with a vertical electric motor positioned above the vertical roll as shown in FIG. 3. The vertical electric motor 11 is positioned on the frame 10 of the vertical rolling mill. The lower end of the drive shaft 11a of the vertical electric motor 11 extends below bearing 12 and is connected to the upper end 13a of an intermediate shaft 13 by a first universal joint 14a. The lower end 13b of the intermediate shaft 13 is connected to the upper end of a vertical roll 15 by a second universal joint 14b. Motive power is thus transmitted from the motor 11 to the vertical roll 15. Although the above-mentioned disadvantages associated with the drive shown in FIG. 2 are eliminated by the driving apparatus shown in FIG. 3, the apparatus of FIG. 3 has the disadvantage of increased overall height due to the additional height of the vertical electric motor 11. Existing building dimensions may be insufficient for installing the vertical rolling mill of FIG. 3. If so, remodeling or new construction would be necessary. It is therefore desirable to provide for a driver for a vertical rolling mill which does not suffer from the disadvantages of the drivers shown in FIGS. 2 and 3.